1. Field of the Invention
The present invention relates to recording/reproducing device and method, a recording medium and a program, for example, which are suitable for use to record video data on an information recording medium such as an optical disc and to transmit the recorded video data.
2. Description of Related Art
In recent years, information recording mediums such as optical discs at a remarkably improved recording rate have been put into practical use. On such information recording mediums, relatively high-quality video data can be recorded for long time.
A conventional optical disc recording device for video images cannot externally transmit a file on a medium while recording is in progress. Therefore, the conventional optical disc recording device has a problem that recording is required to be stopped for transmission.
One of the reasons is that a recording rate is close to a data rate. Thus, the optical disc recording device can scarcely perform recording, and therefore does not have any more capability of performing reproduction. Another reason is as follows. In a case where a constant linear velocity (CLV) method is employed, the number of revolutions is significantly reduced when recording is performed on the outermost track. On the other hand, a sufficient relative speed cannot be obtained on the inner tracks. Therefore, even if two pickups are provided for the device, data on the inner tracks cannot be read out at a speed equal to or higher than single speed.
Since data to be subsequently transmitted are positioned in the relative vicinity, it is highly efficient to collectively read out these data from a disc because the number of seeks is reduced. If a transmission speed fluctuates, however, it happens that a start of readout is too late, or data, which is not required to be immediately read out, is forced to be read out. In data transmission, a transmission speed constantly varies due to busyness or congestion of a transmission line. Therefore, even in a case where recorded data is immediately transmitted through a line that is not too busy, the data may be missing if a transmission speed becomes temporarily low. On the other hand, if data is read out from a disc so as to be transmitted, the readout sometimes catches up with writing. In such a case, the data, which has been just written, is uselessly read out immediately.